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Outdoor Warning Sirens

The Outdoor Warning Sirens will be tested audibly on the first Wednesday of each month at noon if weather conditions are favorable.

These sirens are designed to alert citizens, who are outdoors, to an eminent threat in the community. When sounded, citizens should seek shelter immediately in a stable structure. Once secure, citizens should listen to a radio and/or television for emergency warning details and further instructions.

While tornado warnings are the most common cause for siren activation, the sirens should not be considered to be "tornado sirens." They are intended as an "all-hazards" alerting system and may be activated for any type of emergency situation. The sounding of the sirens does not necessarily mean that a tornado warning has been issued. In fact, it means only that an emergency event has occurred or is about to occur and you may need to take action to protect yourself. If you hear a siren, you should immediately seek additional information through local radio and television stations. In all cases, the siren warning signal is a three minute steady blast with each siren lighting a ring of red LED lights while the sirens are active.

Sirens will be activated for:
• A tornado warning issued by the National Weather Service
• Tornado or funnel cloud reported by a reliable source
• Sustained winds in excess of 70 mph
• Reports or suspected hail larger than 1.25 inches
• Chemical spill emergency
• State or national emergency declared by the governor or president
• Other emergencies as appropriate

The most important thing to know about these sirens is that they are designed to alert individuals who are outdoors. Sirens are not intended to alert people who are in cars, homes, or other buildings. Hearing sirens indoors may have been possible in the past; however, this should no longer be expected. Energy conservation practices and better insulation have effectively reduced the sound penetration into these areas. In addition, many homes and businesses are air-conditioned. Very few buildings have open windows in the summer when it is hot and humid – the very time when severe weather is most likely to occur.

A number of factors affect the range of the siren- sound output, atmospheric conditions, topography and ambient noise levels. Very simply, some sirens are designed to be louder than others. A louder siren will have a greater range. Atmospheric conditions, such as wind speed and direction, air stability, and relative humidity, all affect the distance that the sound will travel. Your ability to hear the siren will change as these conditions change. It is very possible that from your location, in some cases you will be able to hear the siren, while in other cases, you won't. Topography and background noise levels will also have an effect on your ability to hear the sirens. Hills, trees, and buildings can be barriers that block the sound. High background noise levels from highways or industrial areas can mask the sound of the siren. These conditions will effectively limit the warning range of the siren.

Sirens can also be very susceptible to disruptions in the electrical power supply. A majority of the sirens operate on power supplied by local utilities. Power failures, which are common during thunderstorms, can disable a siren. In addition, lightning striking a nearby power line can blow fuses in the siren itself. This will also disable the unit until the fuses can be replaced.

Outdoor Warning Siren Frequently Asked Questions

Q1. When are Sirens Used?Sirens can be activated for a multitude of reasons, including the list below.
• A tornado warning issued by the National Weather Service
• Tornado or funnel cloud reported by a reliable source
• Sustained winds in excess of 70 mph
• Reports or suspected hail larger than 1.25 inches
• Chemical spill emergency
• State or national emergency declared by the governor or president
• Other emergencies as appropriate – as directed by City Management

Q2. Why can’t I hear the siren in my house?Homes are built to insulate against noise and most likely will not allow siren sounds to penetrate inside your home. The warning sirens are designed to be "outdoor" warning sirens only. They are for people who may be outside away from other sources of information. If the forecasters say to take cover, please do so immediately. Do not wait to hear the warning siren to take protective actions inside your home during severe weather.

Q3. When are the sirens tested?Audible testing will occur on the first Wednesday of the month if conditions are favorable. The test will be a full 3-minute audible test.

Testing only occurs when weather conditions are “clear.” This means we will never test the sirens if the weather conditions outside could be confused for a real siren activation.

Q4. Why do we test the sirens so often?It helps conditions the batteries for optimal use and makes sure the sirens are properly functioning. This also makes sure the residents of Garland are familiar with the siren system.

Q5. Why was the siren sounded when it was sunny outside?If you are hearing them on Wednesday at lunch, it is probably the result of a test.

However there may also be instances where there is severe weather in one part of Garland, but not another. We must err on the side of caution and sound the sirens to warn the residents in the warning area even if it means that we warn some that are not in danger.

Q6. What do you do when a siren sounds?If you hear the sirens, seek sturdy shelter immediately. Make your way to an interior room, away from windows and exterior walls, and turn on a radio or television to a local station for more information about what the specific hazard is.

Q8. Do the sirens cover all of Garland?No, the sirens were strategically placed to maximize coverage and reach individuals caught outside before dangerous conditions occur. Most sirens are located in outdoor gathering locations such as parks, ball fields, and the mall.